Wind Farm Facilities in Germany Kill Noctule Bats from Near and Far

Abstract

Over recent years, it became widely accepted that alternative, renewable energy may come at some risk for wildlife, for example, when wind turbines cause large numbers of bat fatalities. To better assess likely populations effects of wind turbine related wildlife fatalities, we studied the geographical origin of the most common bat species found dead below German wind turbines, the noctule bat (Nyctalus noctula). We measured stable isotope ratios of non-exchangeable hydrogen in fur keratin to separate migrants from local individuals, used a linear mixed-effects model to identify temporal, spatial and biological factors explaining the variance in measured stable isotope ratios and determined the geographical breeding provenance of killed migrants using isoscape origin models. We found that 72% of noctule bat casualties (n = 136) were of local origin, while 28% were long-distance migrants. These findings highlight that bat fatalities at German wind turbines may affect both local and distant populations. Our results indicated a sex and age-specific vulnerability of bats towards lethal accidents at turbines, i.e. a relatively high proportion of killed females were recorded among migratory individuals, whereas more juveniles than adults were recorded among killed bats of local origin. Migratory noctule bats were found to originate from distant populations in the Northeastern parts of Europe. The large catchment areas of German wind turbines and high vulnerability of female and juvenile noctule bats call for immediate action to reduce the negative cross-boundary effects of bat fatalities at wind turbines on local and distant populations. Further, our study highlights the importance of implementing effective mitigation measures and developing species and scale-specific conservation approaches on both national and international levels to protect source populations of bats. The efficacy of local compensatory measures appears doubtful, at least for migrant noctule bats, considering the large geographical catchment areas of German wind turbines for this species.

Impacts of Wind Energy Development on Bats: A Global Perspective

“…In the USA, fatalities peak in mid-July through early September in most parts of the country (Johnson 2005;Arnett et al 2008;Baerwald and Barclay 2011;Arnett and Baerwald 2013). Studies from Europe demonstrate a similar pattern (e.g., in Germany, where most (about 90 %) bat fatalities at wind turbines occur between mid-July and the end of September; Brinkmann et al 2011;Lehnert et al 2014). Some studies from northern Europe and North America demonstrate smaller peaks of fatalities during spring Rydell et al 2010a).…”

“…Arnett et al (2013a) noted that studies failing to demonstrate statistically significant effects could be explained by lack of treatments being implemented during the study (i.e., winds were either too low or high to enable comparison of treatments). In Portugal, a mitigation study found that estimated mortality at turbine with raised cut-in speed was 0.3 bats/turbine compared to 1.6 bats/turbine at turbines operating normally, which resulted in a 78.5 % reduction in bat fatalities assuming all turbines at the facilities had raised cut-in speed (LEA 2010).…”

“…4. Investigate the extent of migratory activity worldwide, particularly offshore, by international collaboration using a range of techniques [stable isotopes (Voigt et al 2012;Lehnert et al 2014;Baerwald et al 2014), population genetics, potentially GPS tracking, etc.]. Although difficult, it may be possible to gather and pool acoustic data of activity patterns established through automated real-time recorders in numerous wind energy facilities to evaluate spatial and temporal patterns.…”

Sowing the Wind and Reaping the Whirlwind? The Effect of Wind Turbines on Residential Well-Being

“…In fact, for residents who live close to them, wind turbines have been found to have unpleasant noise emissions (see, for example, Knopper and Ollson (2011) or Shepherd et al (2011)) and, most importantly, negative impacts on landscape aesthetics (see, for example, Devine-Wright (2005), Jobert et al (2007), or Wolsink (2007)). Moreover, they have been shown to have negative impacts on biodiversity (see, for example, Lehnert et al (2014)). Just as other electricity generation technologies, thus, wind turbines do not come without negative externalities, which, in general, do not have market prices and, therefore, are typically valued monetarily using stated preference approaches (see, for example, Groothuis et al (2008), Jones and Eiser (2010), or Meyerhoff et al (2010)) or revealed preference approaches (see, for example, Dröes and Koster (2014), Gibbons (2014), or Sunak and Madlener (2014)).…”

Effects of Renewable Energy Production and Infrastructure on Wildlife

“…Although it could seem that different bat species groups are susceptible to wind turbines in America and Europe, it should be taken into account that all migratory tree-roosting bats from America are aerial-hawking, while mortality of migratory species also occurs in Europe but in smaller proportions (64 % in NW Europe, Rydell et al 2010 ; 56 % in Greece, Georgiakakis et al 2012 ;40 % in Portugal, Amorim et al 2012 ). However, a significant proportion of migratory killed bats in Europe belong to resident populations (Lehnert et al 2014 ).…”